Playing late legendary war correspondent Marie Colvin in the new film A Private War took a physical and mental toll on actress Rosamund Pike.

Depicting the harrowing life-and-death moments, the tremendous suffering of innocent people in war-torn regions, and the personal demons it all raised in Colvin left a “hangover,” Pike told the audience at a Women in the World event in Toronto Sunday.

“The moments rub off on your soul somewhere. You have to trick your body into believing it’s all real,” she said. “That’s my job.”

Colvin, an American reporter with The Sunday Times in London, died at 56 in Syria in 2012. She and longtime friend and photographer Paul Conroy had been smuggled into the besieged city of Homs by rebels, even though they knew the extent of the government bombing of the city and that journalists were particularly being targeted.

Women in the World founder Tina Brown said the film comes at a time when “journalism is under threat” and amid shrinking budgets, when more reporters are risking their lives to tell stories from war zones as stringers and freelancers.

“This film reminds us of the cost of journalism,” Brown said.

Since 2011, 123 journalists have been killed in Syria, according to the Committee to Protect Journalists, and since Colvin’s death, more than 500,000 civilians have died in the fighting there.

A Private War, directed by Oscar-nominated documentarian Matthew Heineman and co-starring Stanley Tucci and Jamie Dornan, will premiere on September 14 at the Toronto International Film Festival. Dornan, of Fifty Shades of Grey fame, plays Conroy, who was badly injured in the shelling that killed Colvin and French photographer Rémi Ochlik.

Marie Colvin began her career as a foreign correspondent covering the Middle East for The Sunday Times, and went on to cover some of the most important stories all over the world, including the Sri Lankan civil war — where she lost her eyesight to a Sri Lankan Army grenade — and the civil war in Syria, where she was killed in 2012. (Uli Seit/The New York Times)

Pike said Colvin was not without fear. Rather, she repeatedly chose to do what she feared the most.

“When most of us would turn on our heels, she went forward,” Pike said.

Other war correspondents refused to go to Syria at the time when Colvin took on her final assignment.

“All her colleagues, all of them brave people, said it was beyond their risk threshold but Marie just said, ‘This is what we do,'” Pike told the Toronto audience. “She was counseled against a great many of her assignments but she would always go in the direction of danger.”

Pike, who grew up in London as the only child of opera singers, says she was intrigued by Colvin after reading Marie Brenner’s 2012 Vanity Fair article, “Marie Colvin’s Private War” on which the movie is partly based. She lobbied Heineman for the role from the moment she knew the movie was being made.

For decades, Colvin felt compelled to tell the stories of those who couldn’t tell them themselves. Just hours before her death, she told Anderson Cooper on CNN, “It’s a complete and utter lie that they’re only going after terrorists … The Syrian army is shelling a city of cold, starving civilians.”

But the movie depicts the steep cost Colvin paid for the violence and suffering she bore witness to, including her addictions and her troubled romantic life.

“At one level, reporters are confronted with a lot of human pain, so much pain and yet it’s not your pain to feel. Where do you put it?” said Pike. “Anyone subject to that kind of horror again and again will pay for it. In your quiet moments it will haunt you.”

Colvin suffered from post-traumatic stress disorder and wore an eye patch after being maimed in a grenade attack in Sri Lanka in 2001. She filed her report from her hospital bed.

“Bravery is not being afraid to be afraid,” Colvin said when she accepted an award for her work in Sri Lanka.

“I was interested in the cost of the life choices you make when you choose a career path like that,” Pike said about Colvin, who was known for her sharp wit, gravelly voice and her perchant for swearing and for wearing expensive lingerie under her flak jacket.

Pike spoke extensively with Colvin’s friends and colleagues, studied video of her and approached her role in the film as that of a documentary. She stayed in character whenever she was on set. The movie, parts of which were filmed in Jordan, features Syrian refugees as actors, including many who had survived the siege of Homs.

Pike, 39, is a seasoned film and theater actress accustomed to playing strong women. She starred in Radioactive, playing iconic scientist Marie Curie and earned an Academy Award nomination and widespread critical acclaim in 2014 for her portrayal of master manipulator Amy Dunne in Gone Girl opposite Ben Affleck.

Gone Girl was her first lead in a feature film after years of delivering supporting roles in films such as Pride & Prejudice, An Education, Fracture, Barney’s Version, and Jack Reacher. In 2016, Pike appeared at the Women in the World London Forum where she discussed her role the the film A United Kingdom.

Her long list of credits includes a turn as a Bond girl in 2002’s Die Another Day. Pike recently made headlines when she revealed that she was asked to take her dress off during auditions for the movie. She somehow found the resolve to refuse, as a 21-year-old clerk in a bookstore desperate for the role.

“I just thought if you want to see me in my underwear, you can give me the part first,” she said. She was cast anyway.

Pike, a mother of two boys, ages 6 and 3, with her partner Robie Uniacke, says she was extraordinarily moved at a private screening of A Private War in London for an audience that included young war correspondents.

“They were impressing upon me what a hero she is to them. It gave me goosebumps. They want to be like her.”

Pike, Heineman and Dornan will appear at the Women in the World Summit in Toronto Monday to discuss the film further. Other featured speakers include Prime Minister Justin Trudeau, journalist Katie Couric, IMF managing director Christine Lagarde, and actress and activist Mira Sorvino. Click here to see the full agenda.